Unit 5-Chapters 10, 11, and 17 Flashcards
Vocabulary and Key Concepts
Early scientist proposed ideas about…
…evolution
Theories of geologic change set the stage for…
…Darwin’’s Theory
Evolution
the rpocess of biological change by which descendants come to differ from their ancestors
Species
a group of organisms so similar to one another that they can reproduce and have fertile offspring
Fossils
traces of organisms that existed in the past
catastrophism
states that natural disasters such as floods and volcanic eruptions have happened often during Earth’s long history
gradualism
a principle that states that the changes in landforms result from slow changes over a long period of time
uniformitarianism
proposes that present geologic processes are they key to the past
Darwin observed differences among…
…island species
darwin observed ___ and ___ evidence supporting an ancient earth
fossil; geographic
variation
the difference in the physical traits of an individual from those of other individuals in the group to which it belongs
adaptation
a feature that allows an organism to better survive in it environment
can lead to genetic change in a population over time
several key insights led to Darwin’s idea for…
…natural selection
Natural selection explains how…
…evolution can occur
Natural selection acts on…
…existing variation
artificial selection
process by which hunmans change a species by breeding it for certain traits
humans act as the selective agent
heritability
the ability of a trait to be passed down from one generation to the next
natural selection
a mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals without the beneficial adaptation
population
all the individuals of a species that live in an area
fitness
a measure of the ability to survive and produce more offspring relative to other members of the population in a given environment
evidence for evolution in Darwin’s time came from…
…several sources
structural patterns are clues to the…
…history of a species
biogeography
the study of the distribution of organisms around the world
homologous structures
features that are similar in structure but appear in different organisms and have different functions
strong evidence for common descent
analogous structures
structures that perform a similar function but are not similar in origin-different structures
vestigial structures
remnants of organs or structures that had a function in an early ancestor
molecular and genetic evidence support..
…fossil and anatomical evidence
evolution unites…
…all fields of biology
paleontology
the study of fossils or extinct organisms
Fossils provide a record of…
…evolution
genetic variation in a population increases the…
…chance that some individuals will survive
genetic variation comes from…
…several sources
gene pool
the combined alleles of all of the individuals in a population
allele frequency
a measure of how common a certain allele is in the population
natural selection acts on…
…distribution of traits
natural selection can change the…
…distribution of a trait in one o three ways
normal distribution
the frequency of a trait is highest near the mean value and decreases toward each extreme end range
microevolution
the observable change in the allele frequencies of a population over time
directional selection
a type of selection that favors phenotypes at one extreme of a trait’s range
stabilizing selection
the intermediate is favored and becomes more common in the population
disruptive selection
a type of selection that favors both extreme phenotypes
gene flow is the…
…movement of alleles between populations
genetic drift is a…
…change in allele requencies due to chance
sexual selection occurs when…
…certain traits increase mating success
gene flow
the movement of alleles from one population to another
genetic drift
change in allele frequencies due to chance alone, occuring mosst commonly in small populations
bottleneck effect
genetic drift that occurs after an event greatly reduces the size of a population
founder effect
genetic drift that occurs after a small number of individuals colonize a new area
sexual selection
occurs when certain traits increase mating success
Hardy-Weinberg equilibrium describes…
…populations that are not evolving
The Hardy-Weinberg equatio is used to…
…predict genotype frequencies in a population
there are ___ factors that lead to evolution
five
Hardy-Weinberg equilibrium
very large population (no genetic drift can occur)
No emmigration or immigration (No gene flow can occur)
No mutations (No new alleles can be added to the gene pool)
Random mating (No sexual selection can occur)
No natural selection (All traits must equally aid in survival
the isolation of populations can lead to
…speciation
populations can become isolated…
…in several ways
reproductive isolation
occurs when members of diferent populations can no longer mate successfully with one another
speciation
the rise of two or more species from one existing species
behavioral isolation
isolation caused by differences in courtship or mating behaviors
geographic isolation
isolation that is caused by physical barriers that divide a population into two or more groups
temporal isolation
isolation caused when timing prevents reproduction between populations
evolution through natural selection is…
…not random
species can…
…shape each other over time
species can become…
…extinct
speciation often occurs…
…in patterns
convergent evolution
evolution toward similar characteristics in unrelated species
divergent evolution
when closely related species evolve in different directions and come increasingly different
coevolution
the process in which two or more species evolve in reponse to changes in each other
extinction
the elimination of a species from earth
punctuated equilibrium
states that episodes of speciation occur suddenly in geologic time and are followed by long periods of little evolutionary change
adaptive radiation
the diversification of one ancestral species into many descendent species
Linnaeus developed the…
…scientific naming system still used today
Linnaeus’ classification system has…
…seven levels
The Linnaean classification system has…
…limitations
taxonomy
the science of naming and classifying
taxon
a group of organisms in a classification system
binomial nomenclature
a system that gives each species a two-part scientific name using Latin words
genus
includes one or more physically similar species that are thought to be closely related
classification is always…
…a work in progress
the three domains in the tree of life are…
…Bacteria, Archaea, and Eukarya
Bacteria
includes singlie-celled prokaryotes in the kingdom Bacteria
Archaea
single-celled prokaryotes in the kingdom Archaea
Eukarya
made up of all organisms with eukaryotic cells
